breastfeeding - pretty long

does anyone have any advice on breastfeeding with big boobs and flat nipples? my little girl will be 3 weeks on friday and she has only latched on a few times for less than a minute. i’m a DD and my nipples are pretty much nonexistent (that’s how flat they are) i didn’t get much help from the lactation consultant from the hospital and she really hadn’t eaten in 24 hours so i gave her formula. since then she’s had formula and a few bottles of pumped breast milk. ( i have nothing against formula and planned to supplement anyway) i’ve tried to use a nipple shield, but it’s almost impossible to hold her, the shield, and my boob since i feel like i’m going to suffocate her. i’m at the point where i want to give up completely instead of continuing to risk the heartbreak every time she doesn’t latch. i know my supply will drop eventually because i’m not feeding from the boob and exclusively pumping won’t fit into my everyday life.

TIA